Words & Photos Mike Busselle
Some photographers dismiss the use of filters as being gimmicky and of distorting the truth of a scene, but I find them essential. Most of my work involves exposing onto colour transparency film and this is very intolerant of an imbalance between the colour of the light source and that for which it is balanced.
Daylight transparency film is designed to give an accurate rendering of colours when the subject is illuminated by sunlight with a colour temperature of about 5600 degrees Kelvin - approximating to summer sunlight at mid day. But it can vary from as little as 3000K (very red) close to sunset to as much as 20,000K (very blue) in open shade under a blue sky.
Of course, in many cases, we're not necessarily concerned about the accuracy of colours in a photograph, just whether they are pleasing or not. A landscape with a blue cast, for instance, can look unattractive and uninviting while a portrait can look unpleasant and unflattering when the skin tones are too red. In these cases filters in the Wratten 81 range will correct the blue cast and those in the Wratten 82 range will balance a red cast. I find I use the 81 warm-up filters much of the time when shooting landscapes and buildings as, in most cases, I dislike even a slight blue cast while a slightly warm cast is usually quite pleasing for these particular subjects.
Much stronger filters are also needed to remove the colour cast caused by shooting in artificial light, such as tungsten bulbs and fluorescent tubes, on daylight colour transparency film. But if you shoot on colour negative film the use of colour balancing or correction filters is not so important because any unwanted colour casts can be removed at the printing stage. And with a digital camera the white balance control should remove any colour casts within the camera.
Landscape in South Australian outback, shot using a Canon EOS-1N with a 17-35mm zoom lens, polarising, warm-up and neutral graduated filters on FujichromeVelvia
One filter that benefits all camera users is the polarising filter. Its effect is to eliminate, or reduce, some of the light being reflected from non-metallic surfaces. A blue sky is the classic example as it is created by light being reflected from water droplets in the atmosphere. The effectiveness of the filter will depend upon the relative angles between the camera, the sun and the area of sky being photographed. When these factors are at their optimum the result will be a much denser, more saturated blue sky with any white clouds standing out in bold relief.
Shot in the Arches National Park Utah, USA using a Canon EOS-1V with a 70-200mm zoom lens, polarising and warm-up filters on Fujichrome Velvia
A polarising filter will also improve the colour quality of still water and make it appear more translucent and it can dramatically increase the colour saturation of foliage such as grass and leaves, especially on a dull day. The degree of effectiveness is partly controlled by rotating the filter and it's not always desirable to have it at full blast, especially when photographing a blue sky on a wide-angle lens as it can make one side of the image noticeably darker than the other.
Winter landscape near Boulogne, France shot using a Mamiya 645 with a 105-210mm zoom lens, polarising, warm up and neutral graduated filters on Fujichrome Velvia
A polarising filter will need one and a half to two stops more exposure but when using TTL metering bear in mind that if the filter makes a blue sky much darker the meter will suggest more exposure than is actually needed. Two types can be bought, linear and a circular polariser. Both have much the same effect, but the latter is recommended for use with autofocusing cameras and is less likely to interfere with TTL metering systems.
Photographed in the Dombes region of France using a Mamiya 645 with a 55-110mm zoom lens, warm up and neutral graduated filters on Fujichrome Velvia film.
Another filter that I find invaluable, especially for landscape photography, is the neutral graduated filter. Half the filter is tinted grey and the other half is clear, with a gradual transition between them. Its most useful application is to reduce the brightness of the sky and make it record as a darker tone. It's the colour photographer's equivalent of the darkroom technique of burning in.
You can also use it on the lower half of the image, to make a foreground darker, for instance, or on one of the sides to balance uneven illumination. Although you can buy round graduates, that screw directly onto the lens mount, they are of limited use as you do need to be able to adjust the position of the filter and, for this, a square filter holder with a slot is needed.
A graduated filter can overcome the potential problem of underexposure when a large area of bright sky is included in the frame. But if you are using the filter to emphasise the effect of a dark, stormy sky it's best to use the exposure setting indicated before the filter is fitted, otherwise you are likely to overexpose. Graduated filters can also be bought in a wide variety of colours but you do need to use them very discriminatingly if you wish to avoid obvious and unnatural-looking results.
Autumn scene in the Forest of Compiegne, France using a Mamiya 645 with a 55-110mm zoom lens, polarising and warm up filters on Fujichrome Velvia film.
Hawks Nest Bay in the US Virgin Island of St John using Nikon F4 with a 20-35mm zoom lens, polarising, and warm-up filters on Fujichrome Velvia.
Landscape in the south downs near Alfriston, Sussex using a Mamiya 645 with a 55-110mm zoom lens, polarising, warm up and neutral graduated filters on Fujichrome Velvia.